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# Bitcoin Oridinals
# BRC20

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# Agenda

- How Ordinals NFTs Work
- Where and How to inscribe (Inscriptions)
- BRC20
- 其他衍生協議
- 總結

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## Ordinals

- <span class="medium">總共有 21,000,000 顆BTC</span>
- <span class="medium">1顆 BTC 可分成最小單位 100,000,000 Satoshi (聰 SAT)</span>
- <span class="medium">Ordinal Theory Rarity</span>
-- <span class="medium">common: Any sat that is not the first sat of its block</span>
-- <span class="medium">uncommon: The first sat of each block</span>
-- <span class="medium">rare: The first sat of each difficulty adjustment period</span>
-- <span class="medium">epic: The first sat of each halving epoch</span>
-- <span class="medium">legendary: The first sat of each cycle (6 halving)</span>
-- <span class="medium">mythic: The first sat of the genesis block</span>

<span class="small">Ref: [Ordinal Theory Handbook](https://docs.ordinals.com/overview.html)</span>

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## UTXO


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## UTXO Coinbase


- Coinbase Transaction:
-- special tx
-- no input and one or more outputs
-- rewards + gas fee

[Bitcoin Exploer](https://www.blockchain.com/explorer/blocks/btc/)

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## Where to inscribe

- 從2017年 SegWit 升級 (BIP141) 後，Witness data 從交易數據中分離出來
- SegWit升級後，Transaction size (body + witness) 最大是 4MB
- 錢包地址開頭為 bc1q


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## How to inscribe

- 從2021年 Taproot 升級後 (BIP342)，可以在bitcoin上寫智能合約(tapscript)
- 錢包地址開頭為 bc1p

OP_FALSE
OP_IF
  OP_PUSH "ord"
  OP_1
  OP_PUSH "text/plain;charset=utf-8"
  OP_0
  OP_PUSH "Hello, world!"
OP_ENDIF

<span class="small">Ref: [Ordinal Theory Handbook](https://docs.ordinals.com/inscriptions.html)</span>

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## Witness brc20 example

- $ORDI [deploy]
-- [blockchain explorer](https://www.blockchain.com/explorer/transactions/btc/b61b0172d95e266c18aea0c624db987e971a5d6d4ebc2aaed85da4642d635735)
-- [unisat](https://unisat.io/inscription/b61b0172d95e266c18aea0c624db987e971a5d6d4ebc2aaed85da4642d635735i0)
- $ORDI [mint]
-- [blockchain explorer](https://www.blockchain.com/explorer/transactions/btc/85defa9d5eabcd4694a69d1194324e305c6a541d569835fc609f1e0f736dde11)
-- [ordinals](https://ordinals.com/tx/85defa9d5eabcd4694a69d1194324e305c6a541d569835fc609f1e0f736dde11)

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## Ordinals Dune 統計


<span class="medium">Ref: https://dune.com/cryptokoryo/brc20</span>

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### BRC-20 起源

<a href="https://twitter.com/domodata/status/1633658974686855168"></a>

<span class="medium">[brc-20-experiment](https://domo-2.gitbook.io/brc-20-experiment/)</span>

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## BRC-20 operation

- deploy, mint, transfer


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## ORC-20


<span class="small">https://docs.orc20.org/</span>

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## ORC-20


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### BRC-21

<a href="https://twitter.com/alexeiZamyatin/status/1655178428180492289"></a>

<span class="small">[BRC-21 Token Standard](https://interlay-labs.gitbook.io/brc-21/)</span>

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## 總結

- 在 bitcoin 的 witness 寫 inscription 而創造 brc-20 token
- bitcoin 的智能合約 tapscript 受限，無法使用合約交互得知各個地址brc-20目前狀態
- 依賴於中心化的 indexer 解析 inscription 數據而拆分出brc-20狀態
- 因 bitcoin 網路出塊時間約10分鐘，而brc-20的Transfer需兩步驟，導致UX很差

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## Reference

- https://medium.portto.com/dive-into-how-bitcoin-ordinals-nfts-work-ca5634da73d
- https://domo-2.gitbook.io/brc-20-experiment/
- https://unisat.io/
- https://thebitcoinmanual.com/articles/btc-ordinal-explorer/

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# Q & A

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## Bitcoin Unlock / Locking Script


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### Bitcoin address type

- Legacy (P2PKH) 開頭為 1
-- 傳統地址
-- <span class="hl">1</span>5e15hWo6CShMgbAfo8c2Ykj4C6BLq6Not

- P2SH 開頭為 3
-- 支援多簽
-- <span class="hl">3</span>5PBEaofpUeH8VnnNSorM1QZsadrZoQp4N

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### Bitcoin address type

- SegWit、bech32 (P2WPKH) 開頭為 bc1q
-- 交易跟簽名分離
-- 允許 3MB 簽名數據和 1MB 的交易數據
-- <span class="medium"><span class="hl">bc1q</span>42lja79elem0anu8q8s3h2n687re9jax556pcc</span>

- Taproot (P2TP) 開頭為 bc1p
-- Schnorr簽章 (BIP340)
-- Taproot (BIP341)
-- Tapscript (BIP342)
-- <span class="medium"><span class="hl">bc1p</span>mzfrwwndsqmk5yh69yjr5lfgfg4ev8c0tsc06e</span>

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## Bitcoin address type



<span class="medium">Reference: https://dune.com/queries/1883950/3103481</span>

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### Bitcoin UTXO


Example:
- <span class="medium">[2 input => 1 output](https://blockstream.info/tx/d99a97db36c665ae9c070fe604c2bcb62b43e79791752380b527cf72c26411d7)</span>
- <span class="medium">[1 input => n output](https://blockstream.info/tx/dea2e11bea2e6e47988c72965d83376b60b90b62afdfb98769216ab69f8ff13b)</span>

<span class="medium">Ref: https://ithelp.ithome.com.tw/articles/10216976</span>